What Is an Inductor Energy Calculator?
This calculator computes the energy stored in an inductor and can also solve for inductance or current from energy. A comparison mode shows how energy scales with current.
Inductor Energy Formula
Energy in joules, inductance in henries, current in amperes.
Why Energy Depends on Current Squared
Because E = ½LI², doubling the current quadruples energy. This means small increases in current have a disproportionately large effect on stored energy.
| Current Change | Energy Change |
|---|---|
| I | 1× |
| 2I | 4× |
| 3I | 9× |
How to Use the Inductor Energy Calculator
- 1Choose what you want to calculate.
- 2Enter the known values.
- 3Select units.
- 4Click Calculate.
- 5Review energy, formula, and related results.
Example Calculations
E from L & I
L = 10 mH, I = 2 A. E = ½ × 0.01 × 4 = 20 mJ.
L from E & I
E = 50 mJ, I = 1 A. L = 2 × 0.05 / 1 = 100 mH.
I from E & L
E = 1 J, L = 200 mH. I = √(2/0.2) ≈ 3.16 A.
Inductor Energy vs Capacitor Energy
| Component | Formula | Field Type |
|---|---|---|
| Inductor | ½LI² | Magnetic |
| Capacitor | ½CV² | Electric |
Safety Notes
Interrupting current in an inductor creates voltage spikes that can damage components or cause dangerous arcing. Large inductors at high current can store significant energy. Always use proper protection circuits (flyback diodes, snubbers) and safety procedures.
Where Inductor Energy Calculations Are Used
Physics homework, RL circuits, switching regulators, flyback converters, energy storage, relay and solenoid circuits, motor design concepts, and electronics labs.
Common Mistakes
- Forgetting the ½ factor.
- Mixing mH and H.
- Ignoring the I² relationship.
- Confusing energy with power.
- Assuming inductors are safe to disconnect abruptly.
Accuracy and Limitations
This calculator assumes ideal inductors. Real inductors have tolerance, winding resistance, core saturation, and frequency-dependent behavior. This tool is educational and should not replace professional electrical design or safety checks.
Frequently Asked Questions
What does an inductor energy calculator do?›
It calculates the energy stored in the magnetic field of an inductor, and can also solve for inductance or current.
What is the formula for inductor energy?›
E = ½LI², where L is inductance in henries and I is current in amperes.
Why is there a ½ in the inductor energy formula?›
Because energy is the integral of the inductor voltage equation. As current ramps up, the average is half the peak.
Why does energy depend on current squared?›
Doubling current doubles both the magnetic flux and the current, so energy scales as the square.
How much energy does a 10 mH inductor store at 5 A?›
E = ½ × 0.01 × 25 = 0.125 J = 125 mJ.
Is inductor energy the same as capacitor energy?›
Both store energy, but capacitors use electric fields (E = ½CV²) and inductors use magnetic fields (E = ½LI²).
Can inductors be dangerous?›
Yes. Interrupting current in an inductor produces voltage spikes that can damage components or cause arcing.
What is the unit of inductor energy?›
Joules (J). Practical values may be in mJ or μJ.
Does inductance tolerance affect stored energy?›
Yes. A 10% tolerance on inductance shifts stored energy by about 10%.
What is the compare mode for?›
It shows how energy changes when current changes, illustrating the I² relationship.
Can I use this for AC circuits?›
This calculates instantaneous energy at a given DC current. AC analysis requires RMS values and reactive power concepts.
Why would I calculate inductor current from energy?›
If you know the energy budget and inductance, you can determine the current the inductor must carry.
Sources / References
Author & technical reviewer
Manish Kumar
PhysicsCalcs tools are reviewed with an educational focus: clear formulas, transparent assumptions, and practical context for students and science learners.
Learn more about Manish